This proposal seeks continuation funding to develop and support a vast archive of large-scale micro-data drawn from over 100 censuses of 23 Latin American countries enumerated over the past half century. These data are a vital component of the Integrated Public Use Micro-data Series (IPUMS), one of the most intensively-used sources for population and health research. Latin America is the only region with surviving micro-data for virtually every country over multiple decades. The improved and expanded database will allow investigators to make comparisons across an entire hemisphere during five decades of transformative change, and will result in substantial new health-related research on the interrelationships of economic development, fertility and mortality decline, international migration, and family change. The Latin American micro-data archive represents a permanent and substantial contribution to the world's population research infrastructure. By making these data easily accessible to researchers and developing comprehensive and comprehensible documentation, the project is stimulating new research that transcends national boundaries and static interpretation. The project has four major goals: (1) Expand the database, adding data for four new countries, new 2010 round samples for countries currently in the database, and new higher-density versions of several existing samples. (2) Enhance data and metadata, including new geographic coding to better support consistent cross- national and cross-temporal analysis, a new internationally-comparable living standard index based on housing characteristics, and new variables to allow more precise variance estimation. (3) Improve data infrastructure and access by implementing a novel database structure, innovative new metadata tools, and multiple new capabilities to simplify data manipulation and reduce redundant effort by researchers. (4) Ensure dissemination and sustainability through user support, training, and outreach, and implementation of a new plan to ensure long-run preservation of the data and metadata. This infrastructure is a basic resource for health research and policy analysis. Models and descriptions of the past underlie both theories of past social change and projections into the future. Accordingly, the data series provides a unique laboratory for the study of health and demographic processes, and provides the empirical foundation we need for developing and testing social and economic models.